CVE-2026-123298 in JetBrains
Summary
by MITRE • 11/06/2026
In JetBrains Hub before 2026.2.52556 sMTP command injection via email verification was possible
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Analysis
by VulDB Data Team • 11/06/2026
The vulnerability identified in JetBrains Hub prior to version 2026.2.52556 represents a critical server-side security flaw rooted in improper input validation and sanitization of user-supplied data within the email verification workflow. This specific instance of command injection allows an attacker to execute arbitrary operating system commands on the host machine running the JetBrains Hub application by manipulating the SMTP configuration or payload during the account registration or password reset process. The root cause lies in the application's handling of email addresses and related metadata, where special characters are not adequately escaped before being passed to underlying shell commands for sending verification emails via Simple Mail Transfer Protocol (SMTP). This lack of robust input sanitization creates a direct pathway for code execution, bypassing standard access controls that would otherwise restrict such operations.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration CWE-78, which describes Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. The flaw typically manifests when the application constructs shell commands dynamically using unsanitized user input. For example, if the SMTP client library or a custom wrapper script invokes system shells to process email headers or recipient lists, an attacker can inject malicious payloads such as semicolons, pipes, or backticks to terminate the intended command and append arbitrary instructions. This exploitation vector is particularly dangerous because it does not require authentication in many scenarios involving initial account verification, allowing unauthenticated actors to achieve remote code execution with the privileges of the JetBrains Hub service process.
The operational impact of this vulnerability is severe, potentially leading to full system compromise. An attacker who successfully exploits this command injection can read sensitive configuration files, exfiltrate database credentials stored on the server, or pivot further into the internal network by executing commands that probe other systems. In a typical deployment, JetBrains Hub manages user identities and access for various JetBrains products; therefore, compromising the hub service may also jeopardize the integrity of associated development tools and repositories if they are integrated with this identity provider. The ability to execute arbitrary code means that attackers can establish persistent backdoors, install malware, or disrupt services by terminating critical processes, resulting in significant downtime and data loss for organizations relying on JetBrains Hub for centralized authentication and user management.
This vulnerability is also relevant to the MITRE ATT&CK framework under technique T1059, Command and Scripting Interpreter, specifically within the context of initial access or privilege escalation depending on the deployment configuration. The exploitation path often involves crafting a malicious email address that triggers the injection during the SMTP handshake or message processing phase. Defense mechanisms such as input validation are insufficient if they rely solely on blacklisting known bad characters; instead, whitelisting approaches and strict parameterization should be employed to prevent shell interpretation of user data. Furthermore, running the application with minimal privileges can mitigate the impact by limiting the scope of commands an attacker can execute even if injection occurs.
To remediate this issue, organizations must upgrade JetBrains Hub to version 2026.2.52556 or later, where the developers have implemented proper input sanitization and secure coding practices for email handling components. In environments where immediate patching is not feasible, network-level controls such as firewalls can be configured to restrict outbound SMTP traffic from the hub server to only trusted mail relays, reducing the attack surface. Additionally, implementing strict content security policies and monitoring system logs for unusual command execution patterns can aid in early detection of exploitation attempts. Regular vulnerability assessments and penetration testing focused on input validation flaws are recommended to ensure that similar weaknesses do not exist in other parts of the application stack.